/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.optimize.evaluation;

import proguard.classfile.*;
import proguard.classfile.util.SimplifiedVisitor;
import proguard.classfile.visitor.*;
import proguard.evaluation.value.*;
import proguard.optimize.OptimizationInfoMemberFilter;
import proguard.optimize.info.*;

/**
 * This ClassVisitor propagates the value of the $VALUES field to the values() method in the simple enum classes that it
 * visits.
 *
 * @see SimpleEnumMarker
 * @author Eric Lafortune
 */
public class SimpleEnumArrayPropagator extends SimplifiedVisitor implements ClassVisitor, MemberVisitor {
    // *
    private static final boolean DEBUG = false;
    /*/
    private static       boolean DEBUG = System.getProperty("enum") != null;
    //*/

    private final MemberVisitor fieldArrayFinder = new MemberDescriptorFilter("[I", this);
    private final MemberVisitor methodArrayPropagator =
        new OptimizationInfoMemberFilter(new MemberDescriptorFilter("()[I", this));
    private final ValueFactory valueFactory = new ParticularValueFactory();

    private Value array;

    // Implementations for ClassVisitor.

    public void visitProgramClass(ProgramClass programClass) {
        // Find the array of the "int[] $VALUES" field.
        array = null;

        programClass.fieldsAccept(fieldArrayFinder);

        if (array != null) {
            // Update the return value of the "int[] values()" method.
            programClass.methodsAccept(methodArrayPropagator);
        }
    }

    // Implementations for MemberVisitor.

    public void visitProgramField(ProgramClass programClass, ProgramField programField) {
        array = StoringInvocationUnit.getFieldValue(programField);
    }

    public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod) {
        // Set the array value with the found array length. We can't use
        // the original array, because its elements might get overwritten.
        Value propagatedArray =
            valueFactory.createArrayReferenceValue("I", null, array.referenceValue().arrayLength(valueFactory));

        if (DEBUG) {
            System.out.println("SimpleEnumArrayPropagator: [" + programClass.getName() + "."
                + programMethod.getName(programClass) + programMethod.getDescriptor(programClass) + "]: propagating ["
                + propagatedArray + "] as return value");
        }

        setMethodReturnValue(programMethod, propagatedArray);
    }

    // Small utility methods.

    private static void setMethodReturnValue(Method method, Value value) {
        ProgramMethodOptimizationInfo.getProgramMethodOptimizationInfo(method).setReturnValue(value);
    }
}
